Scientists have assessed the genes and sleep patterns of no less than 1.3 million people, finding hundreds of genes that are linked to insomnia. The finding could lead to novel treatments that might help many people around the world struggling with sleep deprivation.

Credit: Flickr, Jacob Stewart.

We all occasionally get a bad night’s sleep but about one in ten individuals chronically experience poor sleep. People with insomnia will find it difficult falling asleep or staying asleep, leading to symptoms such as fatigue, low energy, difficulty concentrating, mood disturbances, and decreased performance in work or at school.

The biological mechanisms of insomnia are poorly understood, but studies have suggested that there may be a genetic link, seeing as how poor sleep seems to run in the family. While some genes linked to insomnia have been identified by studies in the past, an international team of researchers recently took it to the next level. The researchers led by Danielle Posthuma, a statistical genetics professor at Vrije University in Amsterdam, combed through a massive genetic database involving 1.3 million people, including those part of the UKBiobank and who took a genetic test with the private company 23andMe.

By associating common genes with sleep patterns, the researchers were able to identify 956 new genes whose variants contribute to the risk of insomnia. They then went a step further and looked at what cell types and brain areas utilize these genes.

Some of the genes play an important role in the functionality of axons — the long, slender projections of a nerve cell, or neurons, which carry electrical impulses. Others were active in neurons found in the frontal cortex and the subcortical nuclei of the brain, which were previously identified in brain imaging studies of people suffering from insomnia.

“Our study shows that insomnia, like so many other neuropsychiatric disorders, is influenced by 100’s of genes, each of small effect. These genes by themselves are not that interesting to look at. What counts is their combined effect on the risk of insomnia. We investigated that with a new method, which enabled us to identify specific types of brain cells, like the so-called medium spiny neurons.” said Posthuma in a statement.

What was especially surprising was that there was little overlap between the newly identified genes and those known to be involved in other sleep traits, such as being a morning or evening person. Instead, there was a lot of overlap with genes involved with depression and anxiety. This suggests that brain circuits that regulate emotions, stress, and tension might be potentially promising targets for treatments for insomnia.

The study published in Nature Genetics highlights the power of recording immense datasets, revealing slight variations that, together, lead to a great effect and which would have otherwise gone unnoticed.

“This study is an immense step forward in understanding the genetic background of insomnia. The findings underline that insomnia is a serious condition, because of the shared genetic risk of psychiatric disorders metabolic disturbances involved in obesity and diabetes”, states Vladimir Vacic, Senior Scientist in Computational Biology at 23andMe.